Redundant vs Tautology - What's the difference?

redundant | tautology |

As a adjective redundant

is superfluous; exceeding what is necessary.

As a noun tautology is

(uncountable) redundant use of words.




(en adjective)
  • Superfluous; exceeding what is necessary.
  • Repetitive or needlessly wordy.
  • (chiefly, British) Dismissed from employment because no longer needed; as in "rendered redundant".
  • Duplicating or able to duplicate the function of another component of a system, providing back-up in the event the other component fails.
  • * 2013 , Tom Denton, Automobile Electrical and Electronic Systems , page 142:
  • The two lines are mainly used for redundant and therefore fault-tolerant message transmission, but they can also transmit different messages.


    * non-redundant




  • (uncountable) redundant use of words
  • It is tautology to say, "Forward Planning".
  • (countable) An expression that features tautology.
  • ''The expression "raze to the ground" is a tautology, since the word "raze" includes the notion "to the ground".
  • * 1946 , Bertrand Russell, History of Western Philosophy :
  • Pure mathematics consists of tautologies , analogous to ‘men are men’, but usually more complicated.
  • (countable, logic) A statement that is true for all values of its variables
  • Given a Boolean A, "A OR (NOT A)" is a tautology .
    A logical statement which is neither a tautology nor a contradiction is a contingency.
    A tautology''' can be verified by constructing a truth tree for its negation: if all of the leaf nodes of such truth tree end in X's, then the original (pre-negated) formula is a '''tautology .


    * contradiction in terms * (in logic) contradiction * (literary) oxymoron

    Coordinate terms

    * (in logic) contingency, contradiction

    Derived terms

    * tautological * tautologically * tautologise * tautologist * tautologous * tautologously

    See also

    * pleonasm * redundancy * (Tautology) English words suffixed with -ology